For me, Bangkok Patio is the perfect location.
It's in a quiet soi, parallel to Phahonyothin road and within 5 minutes walk Exit 3 at Sanam Pao BTS. I've stayed here several times and the rooms are great. I've used both the 2 bedroom apartment rooms and the Studio. The studio was this trip and it was awesome.
Proper cooking facilities. Lots of water in the fridge for my 11 night stay, one clean in the middle of the stay which the cleaning ladies were happy to shift to another day when I was busy. Balconies on both sides are awesome and for me an important part for any hotel room!
Washing machines AND DRYERS :O are free, located on the second floor. Just get some washing detergent.
Pool and Gym are on the third floor and both adequate and usually quiet enough. Parking on site is a nice touch and the staff are lovely.
I forgot my clothes in the washing machine one day and came back 5 hours later only to find them in the dryer, all sorted and ready to fold. STAY HERE!